Title:
HIGH-STRENGTH COLD-ROLLED STEEL SHEET WITH EXCELLENT MANUFACTURING STABILITY, AND METHOD OF MANUFACTURING THE SAME
Document Type and Number:
Japanese Patent JP2012237069
Kind Code:
A
Abstract:
To obtain a high-strength cold-rolled steel sheet having excellent press formability, decreased cooling rate dependency of strength and excellent manufacturing stability.
This steel sheet contains, by mass, 0.03 to 0.12% C, 0.1 to 0.6% Si, 1.5 to 3.0% Mn, ≤0.10% P, ≤0.01% S, 0.01 to 0.1% Al, ≤0.005% N, 0.0005 to 0.005% B, either or both of 0.005 to 0.05% Ti and 0.005 to 0.05% Nb, and the balance Fe with inevitable impurities, wherein the structure of the steel sheet (excluding the structure in the region between the surface of the steel sheet and a position at a depth of 20 μm from the surface of the steel sheet) is composed of tempered martensitic single-phase structure, and the tensile strength is ≥980 MPa.
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Inventors:
TAJI YUUKI
FUJITA TAKESHI
SASAKI SHIGETO
FUJITA TAKESHI
SASAKI SHIGETO
Application Number:
JP2012158128A
Publication Date:
December 06, 2012
Filing Date:
July 13, 2012
Export Citation:
Assignee:
JFE STEEL CORP
International Classes:
C22C38/00; C21D9/46; C22C38/14
Domestic Patent References:
| JPH09111398A | 1997-04-28 |
Attorney, Agent or Firm:
Hideto Tomabechi